"""Host-side paper_server tools.

PAPER_SERVER_API_KEY stays in the host control plane.  The model receives only
typed business arguments and trimmed JSON / task-local file paths.
"""

from __future__ import annotations

import json
import os
import re
from pathlib import Path
from typing import Any, Optional
from urllib.parse import urljoin, urlparse

import httpx

from .base import Tool

_DEFAULT_BASE_URL = "http://paper.xxhhcty.xyz:8080"
_TIMEOUT = 30.0
_DOWNLOAD_TIMEOUT = 60.0
_MAX_DOWNLOAD_BYTES = 100 * 1024 * 1024
_TYPE_RE = re.compile(r"^[A-Za-z0-9_-]{1,64}$")
_AUTH_ERR_CODES = {"not_authenticated", "authentication_failed", "permission_denied"}
_LIST_FIELDS = (
    "id",
    "doi",
    "title",
    "first_author",
    "first_author_institution",
    "publication_year",
    "publication_date",
    "publication_name",
    "has_fulltext_pdf",
    "has_fulltext_xml",
    "has_abstract",
    "is_oa",
    "type",
    "abstract",
    "pdf_url",
    "xml_url",
)


def _config() -> tuple[str, str, str]:
    base_url = os.environ.get("PAPER_SERVER_URL", _DEFAULT_BASE_URL).strip().rstrip("/")
    api_key = os.environ.get("PAPER_SERVER_API_KEY", "").strip()
    if not api_key:
        raise RuntimeError("PAPER_SERVER_API_KEY env 未设置,无法查询 paper_server")
    return base_url, f"{base_url}/api/resm/paper", api_key


def _params(api_key: str, values: Optional[dict[str, Any]] = None) -> dict[str, Any]:
    result = dict(values or {})
    result["api_key"] = api_key
    return result


def _raise_response_error(response: httpx.Response) -> None:
    err_code = ""
    if response.status_code in (400, 401, 403):
        try:
            response.read()
            body = response.json()
            if isinstance(body, dict):
                err_code = str(body.get("err_code") or "")
        except Exception:
            pass
    if response.status_code in (401, 403) or err_code in _AUTH_ERR_CODES:
        raise RuntimeError(
            f"paper_server auth failed (HTTP {response.status_code}, "
            f"{err_code or 'no err_code'}):请管理员检查平台 PAPER_SERVER_API_KEY"
        )
    if response.status_code >= 400:
        # 不调用 raise_for_status():HTTPStatusError 会携带含 api_key 的完整请求 URL。
        raise RuntimeError(f"paper_server request failed (HTTP {response.status_code})")


def _get_json(
    url: str, *, api_key: str, params: Optional[dict[str, Any]] = None
) -> Any:
    try:
        response = httpx.get(
            url,
            params=_params(api_key, params),
            timeout=_TIMEOUT,
        )
    except httpx.RequestError as exc:
        raise RuntimeError(
            f"paper_server connection failed: {type(exc).__name__}"
        ) from None
    _raise_response_error(response)
    try:
        return response.json()
    except ValueError:
        raise RuntimeError("paper_server returned invalid JSON") from None


def _results(data: Any) -> list[dict[str, Any]]:
    values = (
        data.get("results") if isinstance(data, dict) and "results" in data else data
    )
    if not isinstance(values, list):
        raise RuntimeError("paper_server returned an unexpected result shape")
    return [item for item in values if isinstance(item, dict)]


def _is_doi(value: str) -> bool:
    return "/" in value and value.lstrip().startswith("10.")


def _resolve_to_id(id_or_doi: str, api_url: str, api_key: str) -> str:
    value = str(id_or_doi or "").strip()
    if not value:
        raise ValueError("id_or_doi 不能为空")
    if not _is_doi(value):
        return value
    matches = _results(_get_json(api_url + "/", api_key=api_key, params={"doi": value}))
    if not matches:
        raise ValueError(f"doi 未命中:{value}")
    if len(matches) > 1:
        raise ValueError(f"doi 命中多条({len(matches)}):{value}")
    paper_id = str(matches[0].get("id") or "").strip()
    if not paper_id:
        raise RuntimeError("paper_server DOI 查询结果缺少 id")
    return paper_id


def _get_paper(id_or_doi: str) -> dict[str, Any]:
    _base_url, api_url, api_key = _config()
    paper_id = _resolve_to_id(id_or_doi, api_url, api_key)
    data = _get_json(f"{api_url}/{paper_id}/", api_key=api_key)
    if not isinstance(data, dict):
        raise RuntimeError("paper_server returned an unexpected paper shape")
    return data


def _safe_stem(value: str) -> str:
    stem = re.sub(r"[^A-Za-z0-9._-]+", "_", value.strip()).strip("._")
    return stem[:180] or "paper"


def _media_url(raw_url: str, base_url: str) -> str:
    url = urljoin(base_url + "/", raw_url)
    parsed = urlparse(url)
    expected = urlparse(base_url)
    if parsed.scheme not in ("http", "https") or (
        parsed.scheme.lower(),
        parsed.netloc.lower(),
    ) != (expected.scheme.lower(), expected.netloc.lower()):
        raise RuntimeError("paper_server returned an out-of-origin media URL")
    return url


class PaperSearchTool(Tool):
    name = "paper_search"
    description = (
        "Search the platform paper_server metadata collection. "
        "Use publication_type for server-side source-type filtering, e.g. 'book', "
        "'book-chapter' or 'article'. publication_type uses paper_server/OpenAlex raw "
        "values; normalized literature type book_chapter is represented here as raw "
        "'book-chapter'. Prefer English keywords."
    )
    parameters = {
        "type": "object",
        "properties": {
            "keyword": {
                "type": "string",
                "description": "Fuzzy title/author/institution query.",
            },
            "publication_type": {
                "type": "string",
                "description": "Exact raw source type, e.g. book or book-chapter.",
            },
            "year": {"type": "integer", "description": "Exact publication year."},
            "year_gte": {"type": "integer", "description": "Minimum publication year."},
            "year_lte": {"type": "integer", "description": "Maximum publication year."},
            "doi": {"type": "string", "description": "Exact DOI."},
            "first_author": {
                "type": "string",
                "description": "Exact first-author name.",
            },
            "publication_name": {
                "type": "string",
                "description": "Exact journal/container name.",
            },
            "has_pdf": {
                "type": "boolean",
                "description": "Filter by PDF availability.",
            },
            "is_oa": {
                "type": "boolean",
                "description": "Filter by open-access status.",
            },
            "limit": {
                "type": "integer",
                "default": 10,
                "description": "Maximum records, 1-50.",
            },
        },
    }

    def execute(
        self,
        keyword: str = "",
        publication_type: str = "",
        year: Optional[int] = None,
        year_gte: Optional[int] = None,
        year_lte: Optional[int] = None,
        doi: str = "",
        first_author: str = "",
        publication_name: str = "",
        has_pdf: Optional[bool] = None,
        is_oa: Optional[bool] = None,
        limit: int = 10,
    ) -> str:
        raw_type = str(publication_type or "").strip()
        if raw_type and not _TYPE_RE.fullmatch(raw_type):
            return (
                "[Error] publication_type 只能包含字母、数字、下划线或连字符,"
                "最长 64 字符"
            )
        limit = min(max(int(limit), 1), 50)
        params: dict[str, Any] = {"page_size": limit}
        optional = {
            "search": str(keyword or "").strip(),
            "type": raw_type,
            "doi": str(doi or "").strip(),
            "first_author": str(first_author or "").strip(),
            "publication_name": str(publication_name or "").strip(),
        }
        params.update({key: value for key, value in optional.items() if value})
        if year is not None:
            params["publication_year"] = int(year)
        if year_gte is not None:
            params["publication_year_gte"] = int(year_gte)
        if year_lte is not None:
            params["publication_year_lte"] = int(year_lte)
        if has_pdf is not None:
            params["has_fulltext_pdf"] = "true" if has_pdf else "false"
        if is_oa is not None:
            params["is_oa"] = "true" if is_oa else "false"
        try:
            _base_url, api_url, api_key = _config()
            papers = _results(_get_json(api_url + "/", api_key=api_key, params=params))
        except Exception as exc:
            return f"[Error] paper_search failed:{type(exc).__name__}:{exc}"
        trimmed = [
            {key: paper.get(key) for key in _LIST_FIELDS} for paper in papers[:limit]
        ]
        return json.dumps(trimmed, ensure_ascii=False, indent=2)


class PaperGetTool(Tool):
    name = "paper_get"
    description = (
        "Get one complete paper_server metadata record by internal id or exact DOI."
    )
    parameters = {
        "type": "object",
        "properties": {
            "id_or_doi": {"type": "string", "description": "paper_server id or DOI."},
        },
        "required": ["id_or_doi"],
    }

    def execute(self, id_or_doi: str) -> str:
        try:
            paper = _get_paper(id_or_doi)
        except Exception as exc:
            return f"[Error] paper_get failed:{type(exc).__name__}:{exc}"
        return json.dumps(paper, ensure_ascii=False, indent=2)


class PaperFetchTool(Tool):
    name = "paper_fetch"
    description = (
        "Download an available PDF or XML from paper_server into the current task's "
        "papers/ directory. Use the format actually reported by paper_search/paper_get."
    )
    parameters = {
        "type": "object",
        "properties": {
            "id_or_doi": {"type": "string", "description": "paper_server id or DOI."},
            "format": {
                "type": "string",
                "enum": ["pdf", "xml"],
                "description": "File format to download.",
            },
        },
        "required": ["id_or_doi", "format"],
    }

    def __init__(
        self,
        *,
        working_dir: Path,
        base_dir: Optional[Path] = None,
        user_root: Optional[Path] = None,
    ) -> None:
        super().__init__(base_dir=base_dir, user_root=user_root)
        self.working_dir = Path(working_dir)

    def execute(self, id_or_doi: str, format: str) -> str:  # noqa: A002 - JSON tool contract
        file_format = str(format or "").lower().strip()
        if file_format not in {"pdf", "xml"}:
            return "[Error] format 必须是 pdf 或 xml"
        try:
            paper = _get_paper(id_or_doi)
            available_key = f"has_fulltext_{file_format}"
            if not paper.get(available_key):
                reason = (
                    paper.get("fail_reason") or f"no {file_format.upper()} on server"
                )
                raise RuntimeError(f"paper has no {file_format.upper()}:{reason}")
            raw_url = str(paper.get(f"{file_format}_url") or "").strip()
            if not raw_url:
                raise RuntimeError(f"paper {file_format}_url unavailable")
            base_url, _api_url, api_key = _config()
            media_url = _media_url(raw_url, base_url)
            identity = str(paper.get("doi") or paper.get("id") or id_or_doi)
            destination = (
                self.working_dir / "papers" / f"{_safe_stem(identity)}.{file_format}"
            )
            if destination.exists() and destination.stat().st_size > 0:
                return f"saved:{self._display(destination)} (existing)"
            destination.parent.mkdir(parents=True, exist_ok=True)
            partial = destination.with_suffix(destination.suffix + ".part")
            total = 0
            try:
                with httpx.stream(
                    "GET",
                    media_url,
                    params=_params(api_key),
                    timeout=_DOWNLOAD_TIMEOUT,
                ) as response:
                    _raise_response_error(response)
                    with partial.open("wb") as handle:
                        for chunk in response.iter_bytes(chunk_size=64 * 1024):
                            total += len(chunk)
                            if total > _MAX_DOWNLOAD_BYTES:
                                message = (
                                    "paper_server file exceeds "
                                    f"{_MAX_DOWNLOAD_BYTES} bytes"
                                )
                                raise RuntimeError(message)
                            handle.write(chunk)
                partial.replace(destination)
            except httpx.RequestError as exc:
                raise RuntimeError(
                    f"paper_server download connection failed:{type(exc).__name__}"
                ) from None
            finally:
                if partial.exists():
                    try:
                        partial.unlink()
                    except OSError:
                        pass
        except Exception as exc:
            return f"[Error] paper_fetch failed:{type(exc).__name__}:{exc}"
        return f"saved:{self._display(destination)}"